Yellowstone: The World's First and America's Largest Contiguous National Park

Yellowstone National Park holds dual distinction: established March 1, 1872, as the world's first national park, and at 3,471 square miles (8,983 km²), the largest national park in the contiguous United States. (Alaska's Wrangell-St. Elias is larger nationally at 13.2 million acres.)

Why Yellowstone Was First

Its geothermal wonders—half the world's geysers (including Old Faithful), hot springs, mudpots, fumaroles—plus the Grand Canyon of the Yellowstone, abundant wildlife, and the Yellowstone Lake caldera convinced Congress to withdraw it from settlement "for the benefit and enjoyment of the people."

Legacy

Yellowstone birthed the global national park idea—now 4,000+ parks in 100+ countries. It remains the system's crown jewel: a supervolcano's restless heart, a wildlife sanctuary (grizzlies, wolves, bison, elk), and a laboratory of ecological processes—all protected by a radical 19th-century promise that still holds.